Windows PowerShell command on Get-command dumpadm

Manual Pages for UNIX Operating System command usage for man dumpadm

System Administration Commands dumpadm(1M)

NAME

dumpadm - configure operating system crash dump

SYNOPSIS

/usr/sbin/dumpadm [-nuy] [-c content-type] [-d dump-device]

[-m mink | minm | min%] [-s savecore-dir]

[-r root-dir] [-z on | off]

DESCRIPTION

The dumpadm program is an administrative command that

manages the configuration of the operating system crash dump facility. A crash dump is a disk copy of the physical memory of the computer at the time of a fatal system error. When a fatal operating system error occurs, a message describing the error is printed to the console. The operating system

then generates a crash dump by writing the contents of phy-

sical memory to a predetermined dump device, which is typi-

cally a local disk partition. The dump device can be config-

ured by way of dumpadm. Once the crash dump has been written

to the dump device, the system will reboot. Fatal operating system errors can be caused by bugs in the operating system, its associated device drivers and loadable modules, or by faulty hardware. Whatever the cause, the crash dump itself provides invaluable information to your support engineer to aid in diagnosing the problem. As such, it is vital that the crash dump be retrieved and given to your support provider. Following an operating system crash, the savecore(1M) utility is executed automatically during boot to retrieve the crash dump from the dump device and write it to your file system in compressed form, to a file name vmdump.X, where X is an integer identifying the dump. Afterwards, savecore(1M) can be invoked on the same or another system to expand the compressed crash dump to a pair of files named unix.X and vmcore.X. The directory in which the crash dump is saved on reboot can be configured using

dumpadm.

For systems with a UFS root file system, the default dump device is configured to be an appropriate swap partition. Swap partitions are disk partitions reserved as virtual

memory backing store for the operating system. Thus, no per-

manent information resides in swap to be overwritten by the dump. See swap(1M). For systems with a ZFS root file system, dedicated ZFS volumes are used for swap and dump areas. For further information about setting up a dump area with ZFS, see the ZFS Administration Guide. To view the current dump

configuration, use the dumpadm command with no arguments:

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System Administration Commands dumpadm(1M)

example# dumpadm

Dump content: kernel pages Dump device: /dev/dsk/c0t0d0s1 (swap) Savecore directory: /var/crash/saturn Savecore enabled: yes Save compressed: yes

When no options are specified, dumpadm displays the current

crash dump configuration. The example above shows the set of default values: the dump content is set to kernel memory pages only, the dump device is a swap disk partition, the directory for savecore files is set to /var/crash/hostname. savecore is set to run automatically on reboot and save the crash dump in a compressed format.

When one or more options are specified, dumpadm verifies

that your changes are valid, and if so, reconfigures the

crash dump parameters and displays the resulting configura-

tion. You must be root to view or change dump parameters. OPTIONS The following options are supported:

-c content-type

Modify the dump configuration so that the crash dump consists of the specified dump content. The content should be one of the following: kernel Kernel memory pages only. all All memory pages. curproc Kernel memory pages, and the memory pages of the process whose thread was currently executing on the CPU on which the crash dump was initiated. If the thread executing on that CPU is a kernel thread not associated with any user process, only kernel pages will be dumped.

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System Administration Commands dumpadm(1M)

-d dump-device

Modify the dump configuration to use the specified dump device. The dump device may one of the following:

dump-device

A specific dump device specified as an absolute pathname, such as /dev/dsk/cNtNdNsN when the system is running a UFS root file system. Or, specify a ZFS volume, such as /dev/zvol/dsk/rpool/dump, when the system is running a ZFS root file system. swap If the special token swap is specified as the dump

device, dumpadm examines the active swap entries and

selects the most appropriate entry to configure as the dump device. See swap(1M). Refer to the NOTES below for details of the algorithm used to select an appropriate swap entry. When the system is first

installed with a UFS root file system, dumpadm uses

the value for swap to determine the initial dump

device setting. A given ZFS volume cannot be config-

ured for both the swap area and the dump device.

-m mink | minm | min%

Create a minfree file in the current savecore directory indicating that savecore should maintain at least the specified amount of free space in the file system where the savecore directory is located. The min argument can be one of the following: k

A positive integer suffixed with the unit k specify-

ing kilobytes. m

A positive integer suffixed with the unit m specify-

ing megabytes.

A % symbol, indicating that the minfree value should

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System Administration Commands dumpadm(1M)

be computed as the specified percentage of the total current size of the file system containing the savecore directory. The savecore command will consult the minfree file, if present, prior to writing the dump files. If the size of these files would decrease the amount of free disk space below the minfree threshold, no dump files are written and an error message is logged. The administrator should immediately clean up the savecore directory to provide

adequate free space, and re-execute the savecore command

manually. The administrator can also specify an alter-

nate directory on the savecore command-line.

-n

Modify the dump configuration to not run savecore automatically on reboot. This is not the recommended

system configuration; if the dump device is a swap par-

tition, the dump data will be overwritten as the system begins to swap. If savecore is not executed shortly after boot, crash dump retrieval may not be possible.

-r root-dir

Specify an alternate root directory relative to which

dumpadm should create files. If no -r argument is speci-

fied, the default root directory / is used.

-s savecore-dir

Modify the dump configuration to use the specified

directory to save files written by savecore. The direc-

tory should be an absolute path and exist on the system. If upon reboot the directory does not exist, it will be created prior to the execution of savecore. See the NOTES section below for a discussion of security issues relating to access to the savecore directory. The default savecore directory is /var/crash/hostname where

hostname is the output of the -n option to the uname(1)

command.

-u

Forcibly update the kernel dump configuration based on

the contents of /etc/dumpadm.conf. Normally this option

is used only on reboot when starting

svc:/system/dumpadm:default, when the dumpadm settings

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System Administration Commands dumpadm(1M)

from the previous boot must be restored. Your dump con-

figuration is saved in the configuration file for this

purpose. If the configuration file is missing or con-

tains invalid values for any dump properties, the default values are substituted. Following the update, the configuration file is resynchronized with the kernel dump configuration.

-y

Modify the dump configuration to automatically run savecore on reboot. This is the default for this dump setting. See NOTES.

-z on | off

Modify the dump configuration to control the operation of savecore on reboot. The options are on, to enable saving core files in a compressed format, and off, to automatically uncompress the crash dump file. The default is on, because crash dump files can be very large and require less file system space if saved in a compressed format.

EXAMPLES

Example 1 Reconfiguring The Dump Device To A Dedicated Dump Device: The following command reconfigures the dump device to a dedicated dump device:

example# dumpadm -d /dev/dsk/c0t2d0s2

Dump content: kernel pages Dump device: /dev/dsk/c0t2d0s2 (dedicated) Savecore directory: /var/crash/saturn Savecore enabled: yes Save compressed: yes EXIT STATUS The following exit values are returned: 0 Dump configuration is valid and the specified

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System Administration Commands dumpadm(1M)

modifications, if any, were made successfully. 1 A fatal error occurred in either obtaining or modifying the dump configuration. 2 Invalid command line options were specified. FILES /dev/dump Dump device.

/etc/dumpadm.conf

Contains configuration parameters for dumpadm. Modifi-

able only through that command.

savecore-directory/minfree

Contains minimum amount of free space for savecore-

directory. See savecore(1M).

ATTRIBUTES

See attributes(5) for descriptions of the following attri-

butes:

____________________________________________________________

| ATTRIBUTE TYPE | ATTRIBUTE VALUE |

|_____________________________|_____________________________|

| Availability | SUNWcs |

|_____________________________|_____________________________|

System Administration Commands dumpadm(1M)

svc:/system/dumpadm:default

Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed using svcadm(1M). The service's status can be queried using the svcs(1) command. Dump Device Selection When the special swap token is specified as the argument to

dumpadm -d the utility will attempt to configure the most

appropriate swap device as the dump device. dumpadm config-

ures the largest swap block device as the dump device; if no block devices are available for swap, the largest swap entry is configured as the dump device. If no swap entries are present, or none can be configured as the dump device, a warning message will be displayed. While local and remote swap files can be configured as the dump device, this is not recommended.

Dump Device/Swap Device Interaction (UFS File Systems Only) In the event that the dump device is also a swap device, and the swap device is deleted by the administrator using the

swap -d command, the swap command will automatically invoke

dumpadm -d swap in order to attempt to configure another

appropriate swap device as the dump device. If no swap dev-

ices remain or none can be configured as the dump device, the crash dump will be disabled and a warning message will be displayed. Similarly, if the crash dump is disabled and

the administrator adds a new swap device using the swap -a

command, dumpadm -d swap will be invoked to re-enable the

crash dump using the new swap device.

Once dumpadm -d swap has been issued, the new dump device is

stored in the configuration file for subsequent reboots. If a larger or more appropriate swap device is added by the

administrator, the dump device is not changed; the adminis-

trator must re-execute dumpadm -d swap to reselect the most

appropriate device fom the new list of swap devices. Minimum Free Space

If the dumpadm -m option is used to create a minfree file

based on a percentage of the total size of the file system containing the savecore directory, this value is not automatically recomputed if the file system subsequently

changes size. In this case, the administrator must re-

execute dumpadm -m to recompute the minfree value. If no

such file exists in the savecore directory, savecore will default to a free space threshold of one megabyte. If no

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System Administration Commands dumpadm(1M)

free space threshold is desired, a minfree file containing size 0 can be created. Security Issues If, upon reboot, the specified savecore directory is not present, it will be created prior to the execution of savecore with permissions 0700 (read, write, execute by owner only) and owner root. It is recommended that alternate

savecore directories also be created with similar permis-

sions, as the operating system crash dump files themselves may contain secure information. Default for savecore System installation software might reserve a dedicated dump device (for example, a disk slice or a ZFS volume). In such

a case, the dumpadm default can be set to -n, meaning that

savecore does not run automatically when the system reboots. A crash image will be preserved on the dump device. Run /usr/sbin/savecore manually as root to retrieve the crash image and copy it to a file under /var/crash. The crash image will remain on the dump device until overwritten by a later one.

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Manual Pages for UNIX Operating System command usage for man dumpadm

System Administration Commands dumpadm(1M)

NAME

dumpadm - configure operating system crash dump

SYNOPSIS

/usr/sbin/dumpadm [-nuy] [-c content-type] [-d dump-device]

DESCRIPTION

The dumpadm program is an administrative command that

ured by way of dumpadm. Once the crash dump has been written

dumpadm.

configuration, use the dumpadm command with no arguments:

System Administration Commands dumpadm(1M)

example# dumpadm

When no options are specified, dumpadm displays the current

When one or more options are specified, dumpadm verifies

System Administration Commands dumpadm(1M)

device, dumpadm examines the active swap entries and

installed with a UFS root file system, dumpadm uses

System Administration Commands dumpadm(1M)

dumpadm should create files. If no -r argument is speci-

the contents of /etc/dumpadm.conf. Normally this option

svc:/system/dumpadm:default, when the dumpadm settings

System Administration Commands dumpadm(1M)

EXAMPLES

example# dumpadm -d /dev/dsk/c0t2d0s2

System Administration Commands dumpadm(1M)

/etc/dumpadm.conf

Contains configuration parameters for dumpadm. Modifi-

ATTRIBUTES

| ATTRIBUTE TYPE | ATTRIBUTE VALUE |

SEE ALSO

System Administration Commands dumpadm(1M)

svc:/system/dumpadm:default

dumpadm -d the utility will attempt to configure the most

appropriate swap device as the dump device. dumpadm config-

dumpadm -d swap in order to attempt to configure another

command, dumpadm -d swap will be invoked to re-enable the

Once dumpadm -d swap has been issued, the new dump device is

trator must re-execute dumpadm -d swap to reselect the most

If the dumpadm -m option is used to create a minfree file

execute dumpadm -m to recompute the minfree value. If no

System Administration Commands dumpadm(1M)

a case, the dumpadm default can be set to -n, meaning that